Erica Tennenhouse, PhD
Although typically used for heating and thawing in cell culture, water baths have a variety of applications in research labs, from material characterization to histological studies. Whatever the application, those thinking of purchasing a new water bath for their lab should consider the range of available features that can facilitate safety, help avoid contamination, and make the unit flexible and easy to use.
According to Eric Stimac, general manager of Jeio Tech, Inc. (Billerica, MA), water bath safety is all about having over-temperature limiters and audible alarms that warn the users of extreme temperatures. One situation that is best avoided, says Mark Diener, a product manager at JULABO USA, Inc. (Allentown, PA), is having the heater remain on after all the water in the bath has evaporated. It is therefore important to have a safety mechanism in place that can automatically turn the system off when dry running is detected. Lindsey Low, product manager for laboratory baths and circulators at Thermo Fisher Scientific (Waltham, MA), adds that buyers concerned with safety should seek out UL-listed water baths, and that CE and CSA certifications can be helpful to have as well.
When using a water bath, contamination prevention is essential. Toward that end, having a stainless-steel reservoir is a good start, says Low, and transparent covers allow the user to observe the procedure without continually opening the bath. However, users have additional options when it comes to the material of construction. While stainless steel is the most common material, Diener notes that ceramic interiors may be easier to keep clean.
Regularly draining and replacing the fluid in the water bath is another key way to avoid contamination, and buyers should consider how easy that process is going to be. Whether the water bath has a drain built in, and whether the drain is a simple valve that can be easily opened or requires a screwdriver to open, can make a big difference for the user, Diener says. Low mentions two new water bath features that have received positive feedback from Thermo Fisher’s customers: an integrated drain hose that makes the bath cleaner and easier to empty, and removable hinge covers that allow one to retrieve samples without having to place the cover (likely to be dripping with condensation) on the lab bench.
Additional features that make a water bath simpler to use include digital controls, integrated timers, and the ability to operate in both Fahrenheit and Celsius, says Diener. Because baths are typically shared within the lab, says Low, having presets can make it more convenient to switch settings between users. Stimac adds that a calibration feature can save the user time and money by removing reliance on a third-party company to perform calibration.
A water bath must be flexible enough to accommodate the range of samples and devices that will be placed inside it, from test tubes to test tube racks to flasks of all different sizes. For example, if users want to incubate an Erlenmeyer flask that is taller than the depth of the bath, they require a lid that can be configured to allow the neck of the flask to stick out but still cover the rest of the bath to minimize evaporation. Diener notes that ring covers are available to enable such a setup.
Finally, a feature that should not be overlooked is the availability of technical support, says Low, “because you don’t need to be an expert in thermal dynamics to use a bath, but with a phone call, email, or click, you should be able to get expert advice.”
For additional resources on water baths, including useful articles and a list of manufacturers, visit www.labmanager.com/baths-chillers